HILTI X-U to Fasten OSB to Steel WF or HSS

[BSVBD]

The General Contractor wants to fasten OSB roof sheathing to Steel Wide Flanges or HSS with HILTI PAF pins rather than the specified TEK-5 screws.

Genreally, HILTI pins are for fastening light gage steel to the thicker base material, such that, the fastened material is thin, or of gage thickness maximum, such that the PAF pin is "essentially" already engaged in intimate contact with the base material.

FYI, it is NOT recommended to fasten thicker material, i.e. 1/4"+ steel thickness to a base material, since that thickness of steel to be "fastened" is too thick, such that it would slow down, or hinder the PAF from proper or acceptable penetration into the base material. 1/8" or 12 gage may even be too thick to fasten to a base, as is implied by the HILTI Direct Fastening Technical Guide.

So what about OSB or plywood?

Granted OSB is 5/8" (in this case) BUT... it's OSB! OSB would NOT... SHOULD not hinder a PAF so much as to slow it down from penetrating the base material. But, the pin point WOULD be that thickness away from the base!

Would YOU allow it?

Thoughts?

 

[KootK]

I feel as though you'd be changing the mechanics of the fastener's resistance a fair bit. Less pure shear and lots more rollover. I wouldn't do this for any serious diaphragm unless there was some published guidance for doing so. Speaking of which, is there such guidance for using TEK-5 with wood sheathing on steel? I've been looking for a solution like that.

 

[Aesur]

The ESR report for Hilti X-U is here: Link

I have used shot pins to attach wood sheathing to steel before, but it is rare.

 

[phamENG]

Simpson has PAF pins (PDPAWL) specifically designed for fixing wood to concrete and steel. They have a 'built-in' washer (1" dia. I think?) to make sure you don't just shoot through the wood.

Never used them for a diaphragm, so you'd need to look into that.

 

[BSVBD]

Thank you all for your replies!

Kootk... "MY" theory on TEK screws, in this application, is, provided the specification states that the screw must be long enough to penetrate beyond the steel structure a minimum of 3 pitches of thread, if my judgment determines that the fastened / supported material, 5/8" OSB in this case, is thin enough, I am comfortable with that.

My (2) applications are, 1) negligible diaphragm and 2) uplift, where the large washers (phamENG) would assist.

Aesur... Thank you for the ESR. That seems to support my application.

My main concern is this "intimate contact" theory (of mine) that the fastener should "start" with a reasonable rigid "intimate contact" that a metal fixture would provide that wood would not.

I am awaiting a reply from two HILTI reps that have greatly assisted me over the past several years.

Thank you, again, for your replies!

 

[XR250]

Depending on how many Tek5's need to be installed, it might make more sense to bolt a nailer to the beam instead.